Excess flow shutoff valves are useful for automatically isolating pressurized lines when a component in the line is breached. Specifically, excess flow shutoff valves can be used if the line is under internal pressure and a component downstream of the valve fails or if the line is under external pressure and a component upstream of the valve fails.
Related disclosures include U.S. Pat. No. 4,240,458, U.S. Pat. No. 5,067,511, U.S. Pat. No. 5,462,081, U.S. Pat. No. 5,810,057, U.S. Pat. No. 6,131,599, U.S. Pat. No. 6,484,742, U.S. Pat. No. 6,916,362, and U.S. Pat. No. 7,703,472.
Industry desires excess flow shutoff valves suitable for use at high temperatures, e.g. between 600° C. and 1400° C.
Industry desires a compact and economical excess flow shutoff valve that can operate at higher temperatures than those that are currently available commercially.
Industry desires reliable excess flow shutoff valves that will not trip prematurely and will trip consistently at target flow rates.
Industry desires easily modified excess flow shutoff valves that can be easily modified to vary the target flow rate at which the valve trips.
Industry desires an excess flow shutoff valve that is sensitive to relatively small excess flow.
Some isolation devices intended for use at high temperatures are very large, primarily to keep the working parts isolated from the process fluid and at a lower temperature. Industry desires an excess flow shutoff valve which is small and can be installed in-line.
Industry desires an excess flow shutoff valve that has low pressure drop through the valve during normal operating conditions.
Industry desires an excess flow shutoff valve that provides a tight seal upon closing even when the process fluid contains debris.
Industry desires the capability to trip an excess flow shutoff valve on demand.